Audible time-controlled alarm device



Feb. 9, 1965 c. E. s. REEVES 3,168,886

AUDIBLE TIME-CONTRGLLED ALARM DEVICE Filed May 5, 1961 2 Sheets-Sheet 1 ln www INVENTOR ATTORN EYS Feb. 9, 1965 c. E. G. REEVES 3,168,886

AUDIBLE TIME-CONTROLLED ALARM DEVICE Filed May 3. 1961 2 SheeS-Sheefl 2 ATTORNEYS United States Patent O 3,168,886 AIUDIBLE THME-CNTRLLED ALARM DEViCl-E Charles E. Graham Reeves, Summit, Nd., assigner, by

mesme assignments, to Falcon Alarm Company, Springfield, NJ., a partnership Filed May 3, 1961, Ser. No. 107,393 8 Claims. (Cl. 116-24) The present invention relates to an audible time-controlled alarm device.

When working under dangerous conditions, as for example, where gasses or fumes are present, which can be tolerated only for a certain period, it is desirable to have some alarm system by which the worker is informed that the safety period of endurance has elapsed. It may be, however, that the worker remains in the region of danger after the alarm has been sounded, either because of an accident to him or for any other reason. Since the worker may be the only one who might know of his presence in the region or of the fact that the worker has exceeded his stay beyond the safety period of tolerance, this situation may be fatal to him.

One-object of the present invention is to provide a new and improved audible time-controlled alarm device which obviate's or at least materially reduces the incidences of accidents or inadvertences due to the conditions described above.

In accordance with a specific embodiment of the present invention, theA audible time-controlled alarm device is portable and has a iluid pressurized cylinder, an audible pressurerepsonsive signal device connected to the cylinder through a valve, and a timer for controlling the positions of the valve. The timer can be hand-set by a person to a predetermined period which may correspond approximately to the period of tolerance in the region to be occupied by the person. The valve is normally in initial closed position to block the ow between the pressurzied cylinder and the audible signal device, so that the signal device is normally inactive. Near the end of the tolerance period set on the timer, the valve is automatically moved into open position to establish communication between the cylinder and the audible signal device for a transient period, thereby sounding a preliminary alarm during the latter period. After the alarm has been sounded for this transient period, the valve is automatically moved by the timer into closed position to shut oil the alarm and after a short pause, the valve is again automatically moved by the timer into open position at the end of the time set on the timer, whereupon the alarm will be nally sounded continuously and indelinitely. The valve can be manually locked into closed position at any time while the timer is on, so that after the transient alarm hasbeen sounded, the sounding of the iinal alarm can be prevented. With the alarm device of the present invention, the sounding of the linal alarm is an indication that the custodian of the alarm device has failed to lock the device after the preliminary transient alarm has been sounded, due perhaps to the fact that he has been overcome by the dangerous conditions prevailing in the region where he is working or due to other unforeseen causes.

The alarm device may, for example, be employed in the following way: Assuming that a person intends to work or operate in a tank, room, building or enclosure which contains gaseous fumes, or which is on lire or under conditions permitting tolerance for only a certain period, the person sets the timer in the device to a period approximating the tolerance period and enters the enclosure While the alarm device is left outside. Near the set period, the preliminary alarm is sounded for a short period. The person should leave the enclosure and lock the alarm device so that it will not emit the nal alarm. If he fails to lock the device upon the sounding of the preliminary alarm,

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the final alarm will be sounded. This gives a warning outside of the enclosure that someone in the enclosure is in danger.

Various other objects, features andV advantages of the invention are apparent from the following description and from inspection of the accompanying drawings, in which FIG. 1 is a perspective of the audible time-controlled alarm device of the present invention and shown with the locking key detached and ready to be inserted to lock the device against valve operation;

FIG. 2 is a rear view of the audible time-controlled alarm device shown with the rear cover removed to reveal the interior structure of the audible device;

FIG. 3 is a section of the audible time-controlledalarm device taken on line 3 3 of FIG. 2;

FIG. 4 is a detail section showing the valve in conjunction with a cam operated by the timer for moving said valve at cycles predetermined by the setting of the timer, said valve being shown during the period of tolerance set on the timer While the valve is in closed position to block communication between the pressurized cylinder and the audlible signal device;

FIG. 5 is a detail View similar to that of FIG. 4 except that the valve is shown near the end of the set tolerance period and during a transient phase when the valve is temporarily open to establish communication between the pressurized cylinder and the audible signal device to sound a preliminary alarm in said signal device;

FIG. 6 is a detail view similar to that of FIG. 4 except that the valve is shown after the transient preliminary alarm `phase and while the valve is in closed position to shut off communication between the cylinder and the audible signal device, but while the timer isstill operating during the terminal part of the set tolerance period;

FIG. 7 is a detail view similar to that of FIG. 4 except that the valve is shown at the end of the set tolerance period in open position to reestablish pressure communication with the audible signal device, this valve being open because of the failure of the custodian of the alarm device to lock the alarm device during the phase shown in FIG. 6.

Referring to the drawings, there is shown a portable audible time-controlled signal device of the present invention comprising a case 10 housing certain parts of the device to be described and closed by a removable rear cover 11. Outside the case 10 is an audible signal device 12 of the well-known type, which is operated by fluid under pressure and which is shown in the form of a horn of the vibrating membrane or diaphragm type. The signal device 12 is connected to the top wall 14 of the case 10 by a fitting assembly comprising a stud 15 threaded into the bottom of the body of the signal device 12 and passing through said top case wall. A bushing 16 extending from the interior of the case lll) through the top case wall 14 is threaded onto a reduced section of the stud 15 and a pair of positioning nuts 17 threaded on the bushing .are clamped on opposite sides of the top case wall 14.

Inside the case 10 is a cylinder 20 removably secured to the top case wall'14 by the bushing 16. The cylinder 20 is charged with a uid that will create a substantial pressure within the container under normal temperature conditions. An example of such a fluid is a group of halogenated hydrocarbons containing one or more fluorine atoms and particularly monochlorodiiluoromethane known lcommercially as Freon, such as Freon 22. An opening 19 in the front wall 26 of the case 10 permits observation of the contents of the cylinder 2i) through a window thereof, and when the contents of said cylinder is exhausted, the empty cylinder can be refilled in place or can be replaced by a lled one.

Communications between the cylinder 20 and the signal device 12 is established by means of a pair of pipes 21 and 22 interconnected by a valve 23 which in turn is controlled from a timer 24 in a manner to be described. One end of the pipe 21 is connected to the upper end of the cylinder 2t) to serve as an outlet for the cylinder and the other end is connected to the valve 23 to serve as an inlet for said valve. One end o f the pipe 22 is connected to the valve 2.3 to serve as an outlet for said valve and the other end is connected to the signal device I2 to actuate the vibratable part therein.

The timer 24 is mounted inside the case 10 and is of standard construction well known in the art, in which the turning of a handle to a predetermined setting on a dial will operate the timer for a period corresponding to the timer setting. This `timer 24 has a shaft 25 which extends through the front wall 26 of the case and which is connected to a Winder handle 27. Secured to the front case wall 26 is a pin 28 which serves as a stop to limit the initial position of the handle 27 and to limit the terminal position of said handle, as shown in FIG. 1. Secured to the face of the front case wall 26 is a circular dial 31 with graduations corresponding to periods of time for which settings on the timer 24 may be set.

In the operation of the timer 24, assuming that it is desired to set oit the signal device 12 for a iinal alarm at the end of a definite period, the handle 27 is turned clockwise from its initial position shown in FIG. l to the corresponding indication on the dial 3l. This action automatically sets the timer 24 operating. As this timer 24 operates, the handle 27 moves gradually counterclockwise (FIG. l) until it reaches the stop 28 at the end of the set period, whereupon the timer stops operating or operates inactively. Y

For operating the valve 23 into proper positions at different phases according to the setting of thetimer 24, there is secured to the timer shaft 25 a cam 35 on the inside of the case llt). This cam 35 turns with the handle 27 and is moved gradually at constant speed by the timer 24 into successive positions to actuate the valve 23 at different periods in the operating cycle.

The valvle 23 is designed to be operated by the cam 35. For that purpose, the valve 23 is of the plunger slide type comprising a valve body 36 in the form of an elongated rectangular block secured to a plate 37 affixed to the frame of the timer 24 and having an inlet passageway 3S connected to the pipe 21 and an outlet passageway 40 connected to the pipe 22, these passageways extending into a bore 4l in said valve body. Slidable-in the bore 4l is a valve member 42 having an upper stern 43 projecting upwardly therefrom and spring-pressed against the periphery of the cam 35 by a coil spring 44 acting in the lower part of the bore 41 against thelower end of the valve member. The lower section of the valve member 42 comprises a iiange 45 axially spaced from the lower end of the valve stern 43 by a shaft 46 to receive around said shaft a sealing ring 47, shown in the form of an O-ring of elastic material, a flange 4S axially spaced from the ange 45 by an exposed shaft 50 and a flange 51 axially spaced from the flange 48 by a shaft 52 to receive around said shaft 52 and between said ilanges 48 and 51 a sealing ring 53 similar to the sealing ring 47. The flanges 45 and 4S have a diameter which is less than that of the bore 41 to form with the wall of said bore an annular space serving as a passageway for the pressurized uidvowing between the inlet 38 and the outlet 40 of the-valve 23. The sealing rings 47 and 53 bear against the peripheral wall of the bore 41 with resilient sealing pressure preventing the passage of pressurized fluid thereacross.

In certain phases of operation of the cam 35 and the valve member '42, the upward pressure of the spring 44 plus that of the pressurized fluid may jam the cam. To prevent this condition, the valve member 42 has a lower extension comprising two spaced anges 54 and 55 and an intervening sealing O-ring 56 bearing against the wall of the bore 41. These parts 54, 55 and 56 do not affect the control of pressurized iiuid between the inlet 38 and the outlet 40 but remain below said inlet in all positions of the valve.

The cam 35 for moving the valve member 42 is stepped with three radially spaced peripheral cam sections 60, 6l and 62 of arcuate contour concentric with the center of the timer shaft 25 supporting said cam. The adjoining arcuate cam sections 6) and 61 are interconnected by a non-radial cam edge 63. The cam 35 beyond its arcuate cam section 61 has a recess 64 which tapers inwardly towards they arcuate cam section 62 forming the base of said recess and which is wide enough to permit the valve stem 43 to pass freely therethrough until it reaches said cam section 62.

The valve member 42 isl moved upwardly against the peripheral surface of the cam 35 by the spring 44 and follows the contour of this surface as the cam rotates clockwise (FIGS. 4-7) and said surface moves progressively across the top ofthe valve stem 43.

When the valve member 42 is depressed so that it will not interfere with the rotation of the cam 35 counterclockwise (FIG. 7), timer 24 is set from an initial inactive position, this causing the cam to be rotated counterclockwise. In this initial position of the timer 24, the handle 27 is engaging the stop 28, as shown in FIG. l, the cam 35 is in the angular position shown in FIG. 7 and the valve member 42 is in elevated position and extending into the cam recess 64, so that said cam is blocked against rotation. To release the cam 35 for thel setting of the timer 24, it is necessary to depress the valve Vmember 42. For that purpose, there is provided a push rod 70 extending in a bore of the valve body 36 with a slide iit and extending through a slide bearing 7l connected to the top wall 14 of the case 10 to permit the upper end of the push rod to project upwardly above this top case wall. Connected to the upper end of the push rod 7) is a push button 72. AManual downward pressure applied to the push button 72 will move the push rod 70 downwardly in the valve body 36. The valve stern 43 is connected to the push rod 70 by means of a shoulder screw 73 threaded radially through the push rod 7) and extending through a hole in the upper end of the valve stem 43 with a snug rotative tit. With this construction, as the push rod 70 is moved downwardly by the application of manual pressure on the push button 72, the valve member 42 is also moved down with the push rod against the action of the spring 44 out of blocking engagement with the cam 35, so that said cam is free to be rotated by the setting of the timer handle 27.

In order to hold the valve member 42 in the depressed position described to permit the setting of the timer 24, and to lock said valve member in inactive position after the transient signal period has transpired, so that the iinal alarm is not sounded, there is provided a key-controlled lock mechanism comprising an arm 75 inside the case 16 connected to a tumbler, which is journalled in a cylindrical housing 76 secured to the top case lwall 14 and which is rotated by a removable key 77. The push rod 70 has two opposite chordal recesses 78 and the arm 75 is provided with a recess 80 to permit said arm to hook on to the depressed push rod 70 throughsaid chordal recesses. in relation to the depressed push rod 70, it locks said rod against upward movement and in position to release the cam 35 from the blocking action of the valve member 42.

While the push rod'70 is locked in depressed position, the timer handle 27 is set for the desired period and the cam 35 is rotated thereby counterclockwise (FIG. l) to the corresponding position. The key 77 is then turned to release the push rod 70 so that the valve member 42 is urged upwardly by the spring 44 against the periphery of the outer cam section 60. In this position of the valve member 42 shown'in FIG. 4, the valve member When the arm '75 is in this hooked positionwill be so stationed, that the upper sealing ring 47 bears against the outlet 4t) or bears against the wall of the bore di just below said outlet so that ow from the inlet 38 to the outlet 40 is blocked, thereby cutting off communication between the cylinder Ztl and the signal device 12.

During the timing cycle, the cam 35 is rotating gradually clockwise (HG. 4), while the valve member 42 is riding against the arcuate outer cam section 6i), so that the valve member remains in the position shown in FIG. 4 to block fluid communication to the signal device 12. When the cam 35 reaches the rotative position approximately shown in FIG. 5, the sloping cam edge 63 moves opposite the upper end of the valve stern 43 and this permits the valve member 42 to rise progressively upwardly. As the valve member d2 begins to ride along the sloping cam surface 63, the valve member is moved into position so that the sealing ring d'7 is above the center line of the valve outlet llt) while the lower sealing ring 53 is below the center line of the valve inlet 38, thereby providing a passageway between the inlet 3S and outlet d@ for the ow of fluid under pressure from the cylinder 2i) to the signal device 12, as shown in FIG. 5. The valve member 42 and the cam 35 are so designed that the valve 2.3 remains open for a short period as, for example, from ve to seven seconds. During this transient period, a preliminary alarm is sounded and a person who is in a region of limited tolerance should leave that region, push the rod "itl downward by manipulation of the push button 72 to its lowermost position to close the valve 23 and at the same time cause the valve stem i3 to move out of blocking relationship with the cam 35 and turn the key 7'7 to lock the rod against upward movement. Even though the valve 23 has been moved into closed position and locked against spring actuation by the manipulations described, the timer 24 will continue to operate tor a limited period as, for example, for three more minutes after the inner end of the sloping cam edge 63 has passed beyond camming position with relation to the valve stem 43, during which time the cam 35 will continue to rotate clockwise until the recess 64 reaches a position in alignment with the center of the valve stem. Assuming, however, that the person in the region of limited tolerance does not depress the valve member 42 to its lowermost inactive valve closing position after the transient preliminary alarm has been sounded, as described, the valve member will continue to be urged upwardly by the action of the spring 44 against the arcuate cam section 6i. as shown in FIG. 6, in which position, the lowermost sealing ring 53 will be located between the valve inlet 3S and valve outlet 40, so that flow to the signal device 12 will be shut ott.

In this position of the valve member 42, the upward pressure of the tluid on the ilange 5l and the sealing ring 53 in conjunction with the upward force of the spring 44 on the valve member 42 would, in the absence of the llanges 54 and 55 and the sealing ring 5d jam the cam 35. However, with the sealing ring S6 below the inlet 38, as shown in FIG. 6, the uid also applies downward pressure on the ilange 54 and the sealing ring 56, so that the fluid pressures on the anges 51 and 54 and sealing rings S3 and 56 would be equalized, thereby preventing jamming of the cam 35.

When the cam 35 reaches a position in which the cam recess 6d is opposite thervalve stem 43, the valve member i2 will immediately move upwardly into said recess by the action ot the spring 4das shown in FIG. 7. In this elevated position of the valve member 42, the bottom sealing ring 53 will be above the valve outlet 40 leaving a clear passage for the flow of pressurized fluid along the bore t1 between the inlet 38 and the outlet 4b, as shown in FG. 7. Under these conditions, the signal device l2 will again be sounded for a nal alarm, and since tre cam 35 in the position shown in FIG. 7 is at the end of the timer set period, when the timer handle 27 is engaging the stop 28, the cam 3S will remain in jthat position causing this nal alarm to be sounded continuously. This sounding of the nal alarm continuously will indicate that the alarm device has not been shut ott during or soon after the transient'alarm was sounded, when it should have been shut off by manual depression of the valve member 42 through the operation of the push button 72, and indicates that the person in the region of limited tolerance has overstayed his presence in that region, by accident, inadvertence or otherwise.

The alarm device is small andlight and is made easily portable by means of a flexible loop strap anchored at the ends to the sides of the case 10 by means of brackets S6. The alarm device can be employed, for example, when working in enclosures containing dangerous fumes which can be tolerated for only certain periods. Por example, the alarm device can be employed by workers in chemical plants and especially when working in tanks and in other types of enclosures where the gases may become overpowering after a period of toleration. Also, the alarm device may be employed by remen when tighting tires and the aftermaths of explosions or by anyone intending to operate in a region of limited tolerance.

As described, a person who contemplates working under the adverse conditions described may set the timer 24 on the alarm device for a predetermined period, unlock the alarm device to permit the valve member 42 to be resiliently pressed against the cam 35 and perhaps remove the key 77 to prevent anyone from tampering with the alarm device while he is in the region of danger. The alarm device would be left outside this region. Near the end of the toleration period set on the timer 24, the device would sound an alarm for a short period, as for example, tive to seven seconds duration, giving warning that the person should leave the region of danger. If he does leave and lock the alarm device in inactive condition, the iinal continuous alarm will not be sounded. It during a predetermined period after the sounding of the preliminary alarm, as for example, during a three minute period, the alarm device has not been locked, the iinal alarm goes oft continuously, indicating to persons outside the region of danger that a person may be in danger in said region and may require help.

While the invention has been described with particular reference to a specific embodiment, it is to be understood that it is not to be limited thereto but is to be construed broadly and restricted solely by the scope of the appended claims.

What is claimed is:

1. An audible time-controlled alarm device comprising an audible duid-responsive signal device, a pressurized uid container, conduit means between the container and the signal device including a valve, a timer manually settable for any selected period, means automatically responsive to the operation of said timer (l) for opening said valve for a transient period near the end of the timer set period to operate said signal device to sound a preliminary alarm, (2) for closing said valve at the end of said transient period to cease the operation of said signal device, and (3) for again opening said valve at the end of the timer set period to again operate said signal device to sound a nal alarm, and manually controllable means for rendering said valve opening and closing means inoperative after said preliminary alarm is sounded and before said nal alarm is sounded.

2. An audible time-controlled alarm device comprising an audible fluid-responsive signal device, a pressurized fluid container, conduit means between the container and the signal device including a valve, a manually settable timer, and a rotary cam having a drive connection from said timer for automatically setting said cam into angular position corresponding to the setting on said timer when said timer is set and for continuously and gradually rotating said cam during the period set on said timer, said valve having a valve member in cam follower relationship with said cam and operable in valve opening and closing positions according to the angular position of said cam to open and close correspondingly communication between said container and said signal device, said cam having a camming coniiguration causing said valve member to move from a valve closing position to a valve opening position and then to a valve closing position again near the end of the period set on said timer to operate said signal device for a transient alarm, and for causing said valve member to move from valve closing position to valve opening position at the end of the period set on said timer to operate said signal device for a iinal alarm.

3. An alarm device as described in claim 2, comprising l manually operable means for rendering said valve member inoperative in valve closing position to prevent the sound ing of the final alarm.

4. An alarm device as described in claim 2, said valve being of the slide plunger type and said valve member being in the form of a plunger and being spring-pressed towards the cam, said valve member having a valve stem in follower engagement ywith said cam, a push rod connected to said stem for moving said valve member away from said cam into valve closing position when said rod is pushed into a predetermined position, and means for locking said push rod in the latter position to prevent the sounding of the iinal alarm.

5. An audible time-controlled alarm device comprising an audible signal device, a manually settable timer, means automatically responsive to the operation of said timer for operating said signal device for a transient period at a time depending on the setting of said timer to sound a preliminary alarm during said transient period, means automatically responsive to the operation of said timer a predetermined time interval after said preliminary alarm has ceased for operating said signal device again to sound a final alarm, and manually controllable means for rendering the means for operating the signal device for the final alarm inoperative after said preliminary alarm has been sounded while permitting said timer to continue to operate to prevent sounding of said tinal alarm.

6. An audible time-controlled alarm device comprising an audible signal device, a manually settable timer operable only during the period for which it is set, means automatically responsive to the operation of said timer for any selected period for operating said signal device near the end of the timer set period to sound a preliminary alarm for a transient period, means automatically responsive to the operation of said timer a predetermined time interval after said preliminary alarm has ceased for operating said signal device again to sound a final alarm and for continuing indefinitely the operation of said signal device for said iinal alarm after said timer has ceased to operate, and manually controllable means for rendering the means for operating the signal device for the final alarm inoperative after said preliminary alarm has been sounded t prevent sounding of said linal alarm.

7. An audible time-controlled alarm device comprising a hand-portable case, an audible fluid-responsive signal case secured to said case but located on the outside of said case, a pressurized tluid container inside said case, conduit means between the container and the signal device including a valve inside said case, a timer inside said C2 case having a settable handle on the outside of said case by which said timer may be set for any selected period, means automatically responsive to the operation of said timer (l) for opening said valve for a transient period at a time depending on the setting of Said timer to operate said signal device to sound a preliminary alarm, (2) for closing said valve at the end of said transient period to cease the operation of said signal device, and (3) for again opening said valve a predetermined time interval after said signal device has ceased operating to again operate said signal device to sound a final alarm, and manually controllable means supported on said case and accessible for operation from the outside of said case for rendering said valve opening means inoperative after said preliminary alarm has been sounded and before said final alarm has been sounded.

8. An audible time-controlled alarm comprising an audible fluid-responsive signal device, a pressurized fluid container, conduit means between the container and the signal device including a valve controlling flow between said container and said signal device, means for opening and closing said valve, a timer manually settable from an initial inoperative position for controlling the operation of said valve opening and closing means to effect opening of said valve automatically at the end of a selected timerset period and maintain said valve open after said period and to thereby operate said signal device at the end orsaid period, said valve opening and closing means including means for closing said valve while said timer is in said initial inoperative position to render the signal device inoperative, said timer having a manipulable member for selectively manually setting said timer, said valve opening and closing means including means automatically responsive to the operation of said timer for any selected period for opening said valve at a predetermined time interval before the end of the timer-set ieriod to sound a preliminary alarm for a transient period and for then closing said valve before the end of the timeraset period, manually controllable means for closing said valve independently of the operation of said timer and for maintaining said valve closed to prevent the operation of said signal device at the end of the timer-set period, and means for supporting and connecting said container, said conduit means, said valve opening and closing means, said timer with its manipulable setting member and said manually controllable valve closing means into a hand-portable compact unit and maintain said valve open after Said period.

References Cited by the Examiner UNITED STATES PATENTS 1,549,824 8/ 25 Woodring 1 16-24 1,600,527 9/26 Woodring 116-24 2,973,673 9/34 Rice 116-26 2,556,908 6/51 Engholdt 137-624.11 2,840,032 6/58 Reeves 116-112 2,966,877 2/61 Konold et al. 116-65 3,000,344 9/61 Ferrell 116-112 3,060,406 10/62 Wright 340-31 LOUIS t. CArozr, Primary Exarrrirer.

C. W. ROBINSON, Examiner. i

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No 3 ,168 ,886 February 9, 1965 Charfles E. Graham Reeves It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7, line 59, for "case secured" read device sucured column 8, line 47, after "unit" insert a period; lines 47 and 48, strike out "and maintain said valve open after Said per0d."; line 54, for "2,973,673" read 1,973,673

Signed and sealed this 22nd day of June 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. AN AUDIBLE TIME-CONTROLLED ALARM DEVICE COMPRISING AN AUDIBLE FLUID-RESPONSIVE SIGNAL DEVICE, A PRESSURIZED FLUID CONTAINER, CONDUIT MEANS BETWEEN THE CONTAINER AND THE SIGNAL DEVICE INCLUDING A VALVE, A TIMER MANUALLY SET TABLE FOR ANY SELECTED PERIOD, MEANS AUTOMATICALLY RESPONSIVE TO THE OPERATION OF SAID TIMER (1) FOR OPENING SAID VALVE FOR A TRANSIENT PERIOD NEAR THE END OF THE TIMER SET PERIOD TO OPERATE SAID SIGNAL DEVICE TO SOUND A PRELIMINARY ALARM, (2) FOR CLOSING AND VALVE AT THE END OF SAID TRANSIENT PERIOD TO CEASE THE OPERATION OF SAID SIGNAL DEVICE, AND (3) FOR AGAIN OPENING SAID VALVE AT THE END OF THE TIMER SET PERIOD TO AGAIN OPERATE SAID SIGNAL DEVICE TO SOUND A FINAL ALARM, AND MANUALLY CONTROLLABLE MEANS 